title: Graphene-based charge sensors.
abstract: We discuss graphene nanoribbon-based charge sensors and focus on their functionality in the presence of external magnetic fields and high frequency pulses applied to a nearby gate electrode. The charge detectors work well with in-plane magnetic fields of up to 7 T and pulse frequencies of up to 20 MHz. By analyzing the step height in the charge detector's current at individual charging events in a nearby quantum dot, we determine the ideal operation conditions with respect to the applied charge detector bias. Average charge sensitivities of 1.3 × 10(-3)e Hz(-1/2) can be achieved. Additionally, we investigate the back action of the charge detector current on the quantum transport through a nearby quantum dot. By varying the charge detector bias from 0 to 4.5 mV, we can increase the Coulomb peak currents measured at the quantum dot by a factor of around 400. Furthermore, we can completely lift the Coulomb blockade in the quantum dot.
authors.affiliation: JARA-FIT and II Institute of Physics B, RWTH Aachen University, D-52074 Aachen, Germany. Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, D-52425 Jülich, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Neumann
authors.forename: C
authors.initials: C
authors.lastname: Volk
authors.forename: S
authors.initials: S
authors.lastname: Engels
authors.forename: C
authors.initials: C
authors.lastname: Stampfer